一种新型双掺杂多晶硅栅MOSFET的研究

发布时间：2018-01-13 01:27

本文关键词：一种新型双掺杂多晶硅栅MOSFET的研究　出处：《安徽大学》2015年硕士论文　论文类型：学位论文

【摘要】：DDPG MOSFET作为一种新型的MOS器件,它具有提高驱动电流,提高器件的跨导和截止频率等优点。但是经过研究发现该器件仍然存在许多缺陷,例如关态电流和栅泄漏电流都比普通单栅MOS器件大很多,其跨导受到短沟道效应而减小的趋势较为明显。所以针对上述问题,本文在复合栅结构的基础上提出了一种新型器件DDPGPD MOSFET,该器件的创新之处在于近漏端沟道处加入了P+掩埋层并且加厚了D-gate氧化层厚度。本文首先从工艺角度着手,提出了实现DDPGPD的工艺步骤,特别是针对栅的实现以及P+掩埋层加入和D-gate氧化层加厚这三个主要的工艺步骤给出了详细的工艺流程和参数。使用工艺模拟软件TSUPREM设计了DDPGPD工艺制作步骤,并将得到的结构文件导入Medici中进行电学特性模拟。在比较器件性能时首先要建立统一的阀值电压,所以首先对DDPGPD的Vth进行了分析。由于表电势最小值始终保持在S-gate下,因此S-gate浓度增加使器件阈值电压增加；而D-gate农度并不会影响阈值电压但是提高其浓度会增加驱动电流。而当P+掩埋层浓度和D-gate氧化层厚度在适当范围内,对阈值电压和驱动电流都不会产生影响。由于DDPG器件D-gate功函数较低,导致D-gate对沟道控制过强,使得DDPG关态电流和栅泄漏电流都比普通MOS器件大。而DDPGPD有效的减小了关态电流和栅泄漏电流,除此之外对于DIBL效应有更好的抑制效果。分析了DDPGPD瞬态特性,包括栅电容、跨导和截止频率。简化了栅电容的组成成分,给出了栅电容的等效电路,并且与DDPG栅电容比较发现DDPGPD具有更小的栅电容。比较了不同尺寸下DDPGPD, DDPG和NMOSFET的跨导,发现DDPGPD不仅保留了DDPG跨导比NMOSFET大的优点,而且抑制了DDPG跨导受到短沟道效应的影响,使跨导在原有基础上再次提高。最后通过计算得到截止频率,发现DDPGPD具有更大的截止频率,从而具有更快的响应速度。
[Abstract]:As a new type of MOS device, DDPG MOSFET has the advantages of increasing the driving current, increasing the transconductance and cutoff frequency of the device. However, it is found that there are still many defects in the device. For example, the turn-off current and the gate leakage current are much larger than the common single-gate MOS devices, and the transconductance decreases obviously due to the short channel effect. Based on the compound gate structure, a novel device DDPGPD MOSFET is proposed in this paper. The innovation of this device is that the buried P layer is added to the channel near the drain end and the thickness of the D-gate oxide layer is thickened. In this paper, the process steps to realize DDPGPD are put forward from the point of view of technology. Especially for the realization of gate and P. The three main process steps of buried layer addition and D-gate oxide layer thickening are given in detail. The DDPGPD process is designed by using the process simulation software TSUPREM. Suddenly. The structure file is imported into Medici to simulate the electrical characteristics. When comparing the performance of the device, the unified threshold voltage should be established first. Firstly, the Vth of DDPGPD is analyzed. Because the minimum value of potential is always kept at S-gate, the threshold voltage increases with the increase of S-gate concentration. The D-gate field does not affect the threshold voltage but increases the driving current when the concentration of the buried P layer and the thickness of the D-gate oxide layer are in the appropriate range. Because of the low D-gate power function of the DDPG device, the D-gate control of the channel is too strong. The DDPG switch current and the gate leakage current are larger than the ordinary MOS devices, and the DDPGPD effectively reduces the off state current and gate leakage current. The transient characteristics of DDPGPD are analyzed, including gate capacitance, transconductance and cut-off frequency. The composition of gate capacitance is simplified. The equivalent circuit of gate capacitance is given, and compared with DDPG gate capacitance, it is found that DDPGPD has smaller gate capacitance. DDPGPD with different sizes is compared. The transconductance of DDPG and NMOSFET shows that DDPGPD not only retains the advantage of DDPG transconductance larger than NMOSFET. Moreover, the transconductance of DDPG is restrained by short channel effect, so that the transconductance is improved again. Finally, the cutoff frequency of DDPGPD is obtained by calculation, and it is found that DDPGPD has a larger cutoff frequency. Thus, the response speed is faster.
【学位授予单位】：安徽大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN386

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